Approximate prediction of gas core geometry in gas assisted injection molding using a short cut method.: An article from: Polymer Engineering and Science
Book Details
PublisherThomson Gale
ISBN / ASINB000R37ZUS
ISBN-13978B000R37ZU8
AvailabilityAvailable for download now
MarketplaceUnited States 🇺🇸
Description
This digital document is an article from Polymer Engineering and Science, published by Thomson Gale on May 1, 2007. The length of the article is 3675 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.
From the author: A relatively cheap, short cut method for prediction of the form and location of the gas core, and the residual plastic wall thickness in gas assisted injection molding (GAIM) is described. The basis is a steady state, single phase solution for flow of the polymer melt through the channel of interest, without the need to model the gas penetration. The gas-polymer interface position is predicted by an appropriately chosen isovel of the flow. For a prismatic or slowly varying channel, only a two-dimensional developed flow solution is required. For more sharply varying cross sections, and where bends are present, a steady three-dimensional (3D) solution is necessary. When a gas delay is used, during which polymer cools to the cavity walls, a solution for transient conduction in the static melt is carried out before the flow solution. By comparisons with the results of full 3D, transient, two-phase simulations of GAIM, and with experimental results, the short cut method is shown to provide reasonable approximations, and in contrast to other currently used approximate methods, captures thickness variations around the circumference of noncircular channels. The asymmetric gas core location in bends is reproduced, as is the increased plastic wall thickness resulting from cooling during a gas delay. While the full analysis will still be required for complex parts and when high accuracy is required, the described short cut method is likely to prove useful in many other cases. POLYM. ENG. SCI., 47:713-720,2007. [c] 2007 Society of Plastics Engineers
Citation Details
Title: Approximate prediction of gas core geometry in gas assisted injection molding using a short cut method.
Author: A. Polynkin
Publication:Polymer Engineering and Science (Magazine/Journal)
Date: May 1, 2007
Publisher: Thomson Gale
Volume: 47 Issue: 5 Page: 713(8)
Distributed by Thomson Gale
From the author: A relatively cheap, short cut method for prediction of the form and location of the gas core, and the residual plastic wall thickness in gas assisted injection molding (GAIM) is described. The basis is a steady state, single phase solution for flow of the polymer melt through the channel of interest, without the need to model the gas penetration. The gas-polymer interface position is predicted by an appropriately chosen isovel of the flow. For a prismatic or slowly varying channel, only a two-dimensional developed flow solution is required. For more sharply varying cross sections, and where bends are present, a steady three-dimensional (3D) solution is necessary. When a gas delay is used, during which polymer cools to the cavity walls, a solution for transient conduction in the static melt is carried out before the flow solution. By comparisons with the results of full 3D, transient, two-phase simulations of GAIM, and with experimental results, the short cut method is shown to provide reasonable approximations, and in contrast to other currently used approximate methods, captures thickness variations around the circumference of noncircular channels. The asymmetric gas core location in bends is reproduced, as is the increased plastic wall thickness resulting from cooling during a gas delay. While the full analysis will still be required for complex parts and when high accuracy is required, the described short cut method is likely to prove useful in many other cases. POLYM. ENG. SCI., 47:713-720,2007. [c] 2007 Society of Plastics Engineers
Citation Details
Title: Approximate prediction of gas core geometry in gas assisted injection molding using a short cut method.
Author: A. Polynkin
Publication:Polymer Engineering and Science (Magazine/Journal)
Date: May 1, 2007
Publisher: Thomson Gale
Volume: 47 Issue: 5 Page: 713(8)
Distributed by Thomson Gale
